The GODEBUG environment variable in Go is used to enable or configure various debugging-related features within the Go runtime. It provides a way to control runtime-specific behaviors and obtain additional debugging information when running Go programs.
Here's an overview of its purpose and usage:
Purpose:
- Enable specific debugging features or behaviors within the Go runtime.
- Obtain additional runtime information and diagnostics.
Usage:
- Set
GODEBUGto a comma-separated list of key-value pairs to enable specific debug features. - The format is
key1=value1,key2=value2,....
Common Debugging Features:
gctrace=1: Enables garbage collection (GC) trace output, providing information about GC cycles.allocfreetrace=1: Enables allocation and free trace output, useful for tracking memory allocations and deallocations.schedtrace=1000: Enables scheduler tracing with a specified interval (in microseconds).traceback=1: Enables stack traces for all goroutine transitions.cgocheck=1: Enables checks for invalid use of cgo.invalidptr=1: Enables panics for invalid memory accesses.
Example:
# Enable GC trace output and scheduler tracing
GODEBUG=gctrace=1,schedtrace=1000 go run main.goIn this example:
gctrace=1enables GC trace output, providing insights into garbage collection cycles.schedtrace=1000enables scheduler tracing, generating trace information at intervals of 1000 microseconds.
When to Use:
- Use
GODEBUGwhen you need detailed runtime information or debugging output. - Helpful for diagnosing performance issues related to memory management, concurrency, and scheduling.
- Use cautiously as enabling certain debugging features can impact performance.
The GODEBUG environment variable is a powerful tool for gaining insights into the behavior of Go programs at runtime and diagnosing complex issues. However, it's recommended to refer to the official documentation for specific key-value pairs and their implications on program behavior.